Re: [Qemu-devel] [Qemu-block] storing machine data in qcow images?

[Eric Blake]

On 06/05/2018 02:47 PM, Michael S. Tsirkin wrote:

> > > Layer 1:
> > >     The string shall always be a JSON 'object'; i.e. of the form
> > >      { "something": ... , "more": ... }
> > >
> > >     The key strings shall be non-null and non-empty and shall
> > >     be unique.

> > I think it would be simpler if layer 0 simply provided a list of
> > names/value pairs, where names are ascii strings, and values are
> > binary data[1].  It would make layer 1 unnecessary, and allow (3)
> > and (4) to happen.
> >
> > [1] In other words, Rich's proposal of "named blobs":
> > https://www.mail-archive.com/address@hidden/msg37856.html
>
> I think simple is beautiful, too. But assuming they
> really are binary how are blobs encoded?
> Did binary really mean UTF-8 here?

Binary blobs can always be base64 encoded for representation within a 
valid JSON UTF-8 string (and we already have several QMP interfaces that 
utilize base64 encoding to pass through what is otherwise invalid 
UTF-8).  It does inflate things slightly compared to a format that 
allows a raw length coupled with raw data, but that is not necessarily a 
problem.

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org